Interfacial Binding Energy Research Articles

Effect of additives on the interface binding strength of DNAN/HMX melt-cast explosives

ABSTRACT To improve the mechanical property of 2, 4-dinitroanisole (DNAN)/1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) melt-cast explosives, the effects of additives, N-methyl-4-nitroaniline(MNA), polyethylene glycol sorbitanmonostearate-60 (Tween60), and cellulose acetate butyrate (CAB) on the binding energy and mechanical properties were simulated by molecular dynamics. Moreover, to verify the accuracy of the simulation results, the influence of additives on the adhesion work, which was calculated by Young’s equation, was investigated. The simulation results were also verified by Brazilian experiments and scanning electron microscopy (SEM) from macroscopic and microscopic scales, respectively. The results indicate that the binding energy and mechanical properties can be effectively improved by blending with a small amount of additives and CAB is regarded to best improve the mechanical properties of the DNAN/HMX melt-cast explosives. The experimental adhesion works agree well with the simulated outcome. A meaningful finding is that there exists correlation between interface binding energy and the tensile strength, fracture mode of DNAN/HMX melt-cast explosive, the larger binding energy is, the better adhesion of HMX particle to DNAN matrix and the higher tensile strength of the charge is, and the fracture mode of the grain changed from transgranular/intergranular mixed fracture to the pure transgranular fracture.

Mechanical Behavior and Damage of Zinc Coating for Hot Dip Galvanized Steel Sheet DP600

Advanced high strength galvanized steel sheet has been one of the dominant materials of modern automotive panels because of its outstanding mechanical properties and corrosion resistance. The zinc coating thickness of hot dip galvanized steel sheet is only about 10–20 μm, which is a discarded object on the macro level. However, it is obvious to damage and impact on stamping performance. Therefore, this paper takes zinc coating as the research object and builds its mechanical constitutive model based on a nano-indentation test and dimensional analysis theory. We separated the zinc coating from the galvanized steel substrate and constructed a sandwich material model by introducing a cohesive layer to connect the zinc coating and the steel substrate. We obtained the interface binding energy between the zinc coating and the steel substrate through the nano-scratch test. The accuracy of the model is verified by the finite element analysis of hemispherical parts. We used the five-layers element model with 0 thickness cohesive layer to simulate the zinc coating damage of galvanized steel sheet. The hemispherical part drawing experiment is used to verify the feasibility of the finite element analysis results. The results demonstrate that it is more accurate to consider the finite element numerical simulation of the zinc coating, introducing the cohesive element to simulate damage between the coating and the substrate. Drawing depth, stamping force, and the strain of the numerical simulation are closer to the experimental results.

Micro-Mechanism Research into Molecular Chains Orientation Synergistically Induced by Carbon Nanotube and Shear Flow in Injection Molding

For the degree of orderly arrangement of the molecular chains at the interface of nanocomposites, the static and sheared polyethylene (PE)/carbon nanotube (CNT) models and the sheared pure PE model were constructed, and molecular simulation experiments were carried out in comparison. The micro-mechanism of molecular chains orientation, synergistically induced by the carbon nanotube and shear flow in injection molding, was discussed by analyzing the radius of gyration, molecular chain motion, conformation evolution of molecular chains, bond orientation parameter, interface binding energy and atom distribution. The results show that, for the static composite system, the conformation adjustment of PE molecular chains induced by CNT is limited due to the hindrance from the surrounding chains. Thus, the orientation and radius of gyration of molecular chains increase slightly. For the sheared pure PE system, the orientation induced by shear flow is unstable. After the cessation of shear, the molecular chains undergo intense thermal movement and relax quickly. The disorientation is obvious, and the radius of gyration decreases considerably. It is worth noting that for the sheared composite system, shear flow and the CNT have a synergistic effect on the orientation of the molecular chains, which is due to the adsorption effect of the CNT on shear-induced oriented chains and the inhibition effect of CNT on the relaxation of shear-induced oriented chains. Thus, the orientation stability of PE chains is greatly improved, and interface crystallization is promoted. Moreover, because of the more regular arrangement of molecular chains in the sheared composite system, more H atoms and C atoms are close to the surface of the CNT, which increases the van der Waals force, and correspondingly increases the interface binding energy.

Theoretical study on Schottky regulation of WSe<sub>2</sub>/graphene heterostructure doped with nonmetallic elements

采用平面波超软赝势方法研究了非金属元素掺杂对二硒化钨/石墨烯肖特基电子特性的影响. 研究表明二硒化钨与石墨烯层间以范德瓦耳斯力结合形成稳定的结构. 能带结果表明二硒化钨与石墨烯在稳定层间距下形成n型肖特基势垒. 三维电子密度差分图表明石墨烯中的电子向二硒化钨移动, 使二硒化钨表面带负电, 石墨烯表面带正电, 界面形成内建电场. 分析表明, 将非金属原子掺杂二硒化钨可以有效地调控二硒化钨/石墨烯肖特基势垒的类型和高度. C, O原子掺杂二硒化钨时, 肖特基类型由p型转化为n型, 并有效降低了肖特基势垒的高度; N, B原子掺杂二硒化钨时, 掺杂二硒化钨体系表现出金属性, 与石墨烯接触表现为欧姆接触. 本文结果可为二维场效应晶体管的设计与制作提供相关指导.

Orientation Relationships of Pure Tin on Single Crystal Germanium Substrates

The limited number of independent β-Sn grain orientations resulting from the difficulty in nucleating β-Sn during solidification of Sn-based solders has a large effect on the resulting β-Sn grain size and, hence, on overall solder joint performance and reliability. This study analyzes the efficacy of Ge as a heterogeneous nucleation agent for β-Sn by observing the morphologies and orientation relationships of as-deposited, solid-state annealed, and liquid-state annealed pure Sn films on single crystal Ge (100), (110), and (111) substrates. Results from scanning electron microscopy and electron backscatter diffraction showed that the as-deposited Sn films all deposited with a Sn (001)|| z-axis texture, regardless of the underlying Ge substrate orientation. Solid-state annealing at 150 °C for 5 min did not result in significant dewetting of the Sn films, and the films maintained their as-deposited texture of Sn (001)|| z-axis, regardless of the underlying Ge substrate orientation. Liquid-state annealing at 235 °C for 1 min resulted is large-scale dewetting of the Sn films and re-orientation of the Sn films on the various Ge substrates. After solidification, the Ge (100) and (110) single crystal substrates produced patches of dewetted grains of the same orientation but there were no consistent Sn grain textures after liquid-state annealing, suggesting no single orientation relationship. In contrast, solidification on Ge (111) single crystal substrates resulted in isolated grains with a single Sn film texture and an orientation relationship of \( \left( {100} \right)_{\rm{Sn}} \parallel \left( {111} \right)_{\rm{Ge}} {\hbox{and}} \left[ {100} \right]_{\rm{Sn}} \parallel \left[ {110} \right]_{\rm{Ge}} \). Density Functional Theory simulations of the experimentally observed Ge (111) sample orientation relationship and the Ge/Sn cube-on-cube orientation relationship suggest favorable relative interfacial binding energies for both interface orientations.

Polaronic Trions at the MoS2 /SrTiO3 Interface.

The reduced electrical screening in 2D materials provides an ideal platform for realization of exotic quasiparticles, that are robust and whose functionalities can be exploited for future electronic, optoelectronic, and valleytronic applications. Recent examples include an interlayer exciton, where an electron from one layer binds with a hole from another, and a Holstein polaron, formed by an electron dressed by a sea of phonons. Here, a new quasiparticle is reported, "polaronic trion" in a heterostructure of MoS2 /SrTiO3 (STO). This emerges as the Fröhlich bound state of the trion in the atomically thin monolayer of MoS2 and the very unique low energy soft phonon mode (≤7 meV, which is temperature and field tunable) in the quantum paraelectric substrate STO, arising below its structural antiferrodistortive (AFD) phase transition temperature. This dressing of the trion with soft phonons manifests in an anomalous temperature dependence of photoluminescence emission leading to a huge enhancement of the trion binding energy (≈70 meV). The soft phonons in STO are sensitive to electric field, which enables field control of the interfacial trion-phonon coupling and resultant polaronic trion binding energy. Polaronic trions could provide a platform to realize quasiparticle-based tunable optoelectronic applications driven by many body effects.

Micro-scale effects of nano-SiO2 modification with silane coupling agents on the cellulose/nano-SiO2 interface

In this study, molecular dynamics simulations were used to investigate the micro-scale effects of modification of nano-SiO2 with commonly used silane coupling agents (KH550, KH560, KH570, and KH792) on the cellulose/nano-SiO2 interface. The relative optimum silane coupling agent and grafting density for nano-SiO2 modification to improve the cellulose/nano-SiO2 interface were determined. The results showed that at the same grafting density, modification of nano-SiO2 with KH792 yielded the highest interfacial binding energy and binding energy density, the largest number of hydrogen bonds at the cellulose/nano-SiO2 interface, the strongest binding to the cellulose chains, and the largest overlapping area at the cellulose/nano-SiO2 interface. We found that the non-bonding interaction energy played a decisive role in the energy of the model system and the interfacial interaction force mainly consisted of van der Waals forces and the hydrogen-bonding energy. When silane coupling agents with amino groups (KH550 and KH792) were used to modify nano-SiO2, the number of hydrogen bonds at the cellulose/nano-SiO2 interface was larger than that for unmodified nano-SiO2. When silane coupling agents without amino groups (KH560 and KH570) were used to modify nano-SiO2, the number of hydrogen bonds at the cellulose/nano-SiO2 interface was lower than the case for unmodified nano-SiO2. Nano-SiO2 modification with various amounts of KH792 was investigated. The results showed that the interfacial bonding energy increased with grafting density. When the grafting density was 1.57 nm−2, the interfacial bonding energy and number of hydrogen bonds formed at the cellulose/nano-SiO2 interface was relatively stable, which indicates that the interface had reached a relatively stable state. Modification of nano-SiO2 with KH792 achieved the greatest improvement of the cellulose/nano-SiO2 interface; this interface reached a relatively stable state when the grafting density of KH792 was 1.57 nm−2.

Enhanced Cu/graphene adhesion by doping with Cr and Ti: A first principles prediction

Abstract We presented a density functional theory study on doping effects of transition metals (Cr and Ti) on the Cu/graphene interface adhesion. Various undoped Cu/graphene interface structures were constructed using both the sandwich and the surface models. Energetics calculations showed that the interface binding strength only weakly depends on interface coordination. Both interface models predicted the top-fcc coordination type as the most energy-favored, with a low binding energy value. Segregated Cr prefers to substituting for Cu, while Ti occupies a hollow site at the interface. Although the segregation tendencies are both very weak, once present on the interface, both dopants can greatly increase the interface binding energy and improve the adhesion.

Introducing bone-shaped carbon nanotubes to reinforce polymer nanocomposites: A molecular dynamics investigation

Typically, the edges of single-walled carbon nanotubes (SWCNTs) are capped with fullerene hemispheres having the same diameter as the nanotubes. In the present numerical study, a bone-shaped (BS) carbon nanotube (CNT) is introduced in order to test its reinforcing capabilities when used as filler within a polymer matrix. The specific complex molecular structure is composed by a SWCNT, the two open edges of which are appropriately closed with larger fullerenes. Specifically, the tubular shape of the proposed nanofiber (NFB) is achieved by the utilization of the zigzag (10,0) SWCNT while the fullerene C500 is appropriately attached at the nanotube open edges for the formation of two spherical heads. The developed BS NFB is used as reinforcement in a polyethylene (PE) matrix at several mass fractions. Corresponding periodic unit cells are developed and simulated via molecular dynamics (MD) to predict the tensile and shear stress-strain response of the investigated nanocomposites. Additionally, appropriate numerical tests are also conducted for computing the NFB/PE interfacial binding energy and, thus, characterizing the interfacial strength of the nanocomposites. For comparison purposes, all numerical tests are repeated by using as reinforcement the conventionally capped (10,0) SWCNT of the same number of atoms instead of the BS one.

Interfacial Characteristics of Boron Nitride Nanosheet/Epoxy Resin Nanocomposites: A Molecular Dynamics Simulation

The interface between nanofillers and matrix plays a key role in determining the properties of nanocomposites, but the interfacial characteristics of nanocomposites such as molecular structure and interaction strength are not fully understood yet. In this work, the interfacial features of a typical nanocomposite, namely epoxy resin (EP) filled with boron nitride nanosheet (BNNS) are investigated by utilizing molecular dynamics simulation, and the effect of surface functionalization is analyzed. The radial distribution density (RDD) and interfacial binding energy (IBE) are used to explore the structure and bonding strength of nanocomposites interface. Besides, the interface compatibility and molecular chain mobility (MCM) of BNNS/EP nanocomposites are analyzed by cohesive energy density (CED), free volume fraction (FFV), and radial mean square displacement (RMSD). The results indicate that the interface region of BNNS/EP is composed of three regions including compact region, buffer region, and normal region. The structure at the interfacial region of nanocomposite is more compact, and the chain mobility is significantly lower than that of the EP away from the interface. Moreover, the interfacial interaction strength and compatibility increase with the functional density of BNNS functionalized by CH3–(CH2)4–O– radicals. These results adequately illustrate interfacial characteristics of nanocomposites from atomic level.

First principles calculation on the interface behavior of LaAlO3/(Ti,Nb)(C,N)

The present study investigated the binding energy and the crystal, interfacial, and electronic structural stabilities of LaAlO3(1 1 1)/(Ti,Nb)(C,N)(1 1 1) heterogeneous nucleation interfaces and analyzed the effectiveness of LaAlO3 as the heterogeneous nucleus of (Ti,Nb)(C,N) by the application of a first principles method. The results indicated that the lattice constant and elastic modulus of (Ti0.5,Nb0.5)(C0.5,N0.5), which were calculated using the virtual crystal approximation method, were similar to those of the actual crystal. The bonding mode between the (Ti0.5,Nb0.5)(C0.5,N0.5) (1 1 1)/LaAlO3 (1 1 1) interface was determined to be a combination of covalent, ionic, and metallic bonds, and the interface exhibited strong bonding effects. Furthermore, the LaAlO3 (1 1 1) interface contained two termination interfaces: Al and LaO3. The surface energies of the LaO3 and Al terminations exhibited positive and negative correlations with the Al chemical potential, ΔμAl, respectively. For most values of ΔμAl, the surface energy of the LaO3 termination was lower than that of the Al termination, which indicates that the LaO3 termination surface was more stable than the latter. For the LaAlO3 (1 1 1)/MX (1 1 1) interface with different termination types, the LaO3-X-terminated interface exhibited the largest interfacial binding energy. Interfacial atoms exhibited the greatest bond strengths, specifically the covalent and polar covalent bonds formed at the interface, indicating that the LaO3-terminated interface containing La atoms was more likely to act as the heterogeneous nucleus of (Ti,Nb)(C,N).

What is the Binding Energy of a Charge Transfer State in an Organic Solar Cell?

AbstractThe high efficiencies reported for organic solar cells and an almost negligible thermal activation measured for the photogeneration of charge carriers have called into question whether photoinduced interfacial charge transfer states are bound by a significant coulomb attraction, and how this can be reconciled with very low activation energies. Here, this question is addressed in a combined experimental and theoretical approach. The interfacial binding energy of a charge‐transfer state in a blend of MeLPPP:PCBM is determined by using energy resolved electrochemical impedance spectroscopy and is found to be about 0.5 eV. Temperature‐dependent photocurrent measurements on the same films, however, give an activation energy that is about one order of magnitude lower. Using analytical calculations and Monte Carlo simulation the authors illustrate how i) interfacial energetics and ii) transport topology reduce the activation energy required to separate the interfacial electron–hole pair, with about equal contributions from both effects. The activation energy, however, is not reduced by entropy, although entropy increases the overall photodissociation yield.

Molecular Mechanism Research into the Replication Capability of Nanostructures Based on Rapid Heat Cycle Molding

Aimed at the molding of polymer nanostructure parts, the interface model between long- and short-chain polycarbonates (PC) and nickel mold inserts was established by the molecular dynamics method. The molecular mechanism of the replication capability of polymer nanostructure part molding was discussed by analyzing the migration and diffusion of the molecular chain, concentration profile, filling morphology evolution, interface binding energy, and filling rate of conventional injection molding (CIM) and rapid heat cycle molding (RHCM). The results show that nanostructures are filled mainly during the packing stage. A short-chain PC system has a low glass transition temperature (Tg) and viscosity, good fluidity, and a high filling rate, so the replication capability of its nanostructures is good. A long-chain PC system has a fast cooling rate in CIM, its molecular chain motion is blocked, the filling rate is low, and the interface binding energy is small, and so its nanostructures have poor replication capability. However, the high temperature at the nanostructures can be maintained for a long time in RHCM, which promotes Brownian motion in the molecular chains. Under the action of packing pressure, molecular chains can overcome entanglement barriers and viscous resistance. Thus, the polymer concentration profile and filling rate increase with increasing packing pressure, which can produce more van der Waals energy. Furthermore, the evolution process of polymer filling morphology is realized by the Brownian motion of chain segments under packing pressure; that is, the diffusion motion of the molecular chain along the direction of a tube composed of other chains around it. With the increase of temperature or pressure, the migration and diffusion of the molecular chain can be promoted; thus, the replication capability of nanostructure parts for mold cavities can be enhanced.

Evidence of direct Z-scheme g-C3N4/WS2 nanocomposite under interfacial coupling: First-principles study

Understanding is far from satisfactory on the high photocatalytic performances of g-C3N4/WS2 nanocomposites which are experimentally reported. Here, we investigate systematically for the first time the interfacial interactions and electronic properties of triazine-based g-C3N4/WS2 nanocomposites by first-principles calculations. The results confirm the reasonable existence of vdW interaction and typical direct Z-scheme mechanism based on the prominent interfacial binding energies and the energy level lineup at interface. Both energy band structures and work functions show that the conduction and valence band edges of the g-C3N4 layer are more negative than those of the WS2 layer after their intimate contact, respectively. Meanwhile, the interfacial interaction makes WS2 with negative charges and g-C3N4 with positive charges, forming a built-in electric field from g-C3N4 to WS2. Thus, photogenerated e––h+ pairs are separated to different places with prolonged lifetime and high redox potential. This work shines some lights on a direct Z-scheme mechanism for the g-C3N4/WS2 heterostructured photocatalyst.

Improving interfacial and mechanical properties of carbon nanotube-sized carbon fiber/epoxy composites

Carboxyl-functionalized carbon nanotubes (CNTs-COOH) and the amine-functionalized carbon nanotubes (CNTs-NH2) were incorporated into the surface sizing agent of carbon fibers respectively, for modifying the interface between the fibers and the matrix. Experimental analyses of the interfacial shear strength, flexural properties, and inter-laminar shear strength revealed the beneficial effects of the CNTs-COOH and negative impacts of the CNTs-NH2 on the interfacial and mechanical properties of the resulting composites. These results were contrary to the effects of CNTs doped into the epoxy matrix of composites. Furthermore, a molecular dynamics simulations were performed to explore the mechanism of these performances from the viewpoint of the molecular structure, revealing that the interface between the CNT-sized carbon fibers and the epoxy was driven by multiple factors, including the CNT-epoxy interfacial binding energy (IBE), the packing density of the molecular chains, and the steric hindrance of the functionalized CNTs. According to these analyses, two kinds of functionalized CNTs showed different effects at the interface between carbon fiber and resin: the CNTs-COOH on the surface of the carbon fiber tightly bonded to the epoxy and provided effective load transfer between the matrix and fibers, whereas the agglomeration of the CNTs-NH2, the lower IBE between the CNTs-NH2 and the epoxy resin, and the steric hindrance produced by amine functional groups of the CNTs-NH2, resulting in hardly inhibiting the crack growth of the matrix under stress.

Unraveling High-Yield Phase-Transition Dynamics in Transition Metal Dichalcogenides on Metallic Substrates.

2D transition metal dichalcogenides (2D‐TMDs) and their unique polymorphic features such as the semiconducting 1H and quasi‐metallic 1T′ phases exhibit intriguing optical and electronic properties, which can be used in novel electronic and photonic device applications. With the favorable quasi‐metallic nature of 1T′‐phase 2D‐TMDs, the 1H‐to‐1T′ phase engineering processes are an immensely vital discipline exploited for novel device applications. Here, a high‐yield 1H‐to‐1T′ phase transition of monolayer‐MoS2 on Cu and monolayer‐WSe2 on Au via an annealing‐based process is reported. A comprehensive experimental and first‐principles study is performed to unravel the underlying mechanism and derive the general trends for the high‐yield phase transition process of 2D‐TMDs on metallic substrates. While each 2D‐TMD possesses different intrinsic 1H‐1T′ energy barriers, the option of metallic substrates with higher chemical reactivity plays a significantly pivotal role in enhancing the 1H‐1T′ phase transition yield. The yield increase is achieved via the enhancement of the interfacial hybridizations by the means of increased interfacial binding energy, larger charge transfer, shorter interfacial spacing, and weaker bond strength. Fundamentally, this study opens up the field of 2D‐TMD/metal‐like systems to further scientific investigation and research, thereby creating new possibilities for 2D‐TMDs‐based device applications.

Molecular docking of anti-inflammatory drug diclofenac with metabolic targets: Potential applications in cancer therapeutics

Diclofenac is a potent NSAID of clinical choice, which is widely used for containing inflammation. Moreover, recent experimental evidences overwhelmingly substantiate its antineoplastic potential. However, the precise molecular mechanisms of diclofenac's anticancer activity remain poorly understood. Neoplastic cells display reprogrammed metabolic features, which are manifested and regulated by a complex networking of molecular pathways. However, the effect of diclofenac on tumor cell metabolism are not yet clearly deciphered. Hence, the present investigation was carried out to identify and characterize key diclofenac targets of tumor metabolism, cell survival and chemoresistance. The interactions of diclofenac with such targets was analysed by PatchDock and YASARA (Yet Another Scientific Artificial Reality Application). The docking ability of diclofenac with its targets was based on analysis of dissociation constant (Kd), geometric shape complementarity score (GSC score), approximate interface area (AI area) and binding energy. The findings of this investigation reveal that diclofenac is capable of interacting with all of the selected molecular targets. Prominent interactions were observed with GLUT1, MCT4, LDH A, COX1, COX2, BCRP/ABCG2, HDM2/MDM2 and MRP1 compared to other targets. Interactions were of noncovalent nature involving ionic, hydrophobic interactions, Van der Waals forces and H-bonds, which varied depending on targets. This study for the first time, characterizes the nature of molecular interactions of diclofenac with selected targets involved in cancer cell metabolism, pH homeostasis, chemosensitivity, cell signalling and inflammation. Hence, these findings will be highly beneficial in optimizing the utility of diclofenac in development of novel cancer therapeutics.

Molecular dynamics modeling of the structure, dynamics, energetics and mechanical properties of cement-polymer nanocomposite

Efforts to tune the performance of organic/inorganic composites are hindered owing to a lack of knowledge related to the interfacial interaction mechanisms. Here we investigated the interfacial structure, dynamics, energetics and mechanical properties between calcium silicate hydrates (C-S-H) and polymers by molecular dynamics (MD) simulation. In this work, polyethylene glycol (PEG), polyvinyl alcohol (PVA) and polyacrylic acid (PAA) are intercalated into nanometer channel of C-S-H sheets to construct the model of polymer/C-S-H composite. In the interfacial region, the calcium ions near the surface of C-S-H play mediating role in bridging the functional groups in the polymers and oxygen in the silicate chains by forming Os-Ca-Op bond. In addition to ionic bonding, the bridging oxygen (C-O-C) in the PEG, hydroxyl (C-OH) in the PVA and carboxyl groups (-COOH) in the PAA provide plenty oxygen sites to form H-bonds with silicate hydroxyl, interlayer water and calcium hydroxyl in C-S-H substrate. The interfacial binding energy is dependent on polarity of functional groups in the polymers, the stability of the H-bond and Ca-O bond, ranking in the following order: E(PAA)> E(PVA) > E(PEG). The PVA with small number of H-bonds formed between oxygen in PVA and water molecules, resulting in increasing the mobility of confined water in the interlayer region. On the other hand, PAA and PVA, with strong polarity, can provide more number of non-bridging oxygen sites that widely distributed along the polymer chains to associate with more calcium ions and H-bonds. Furthermore, uniaxial tensile test is utilized to study the mechanical behavior of the composites. The incorporation of polymers, strengthening the H-bonds in the interfacial region and healing the defective silicate chains, can inhibit the crack growth during the loading process, which both enhance the cohesive strength and ductility of the C-S-H gel. In particular, the intercalated PAA increases the Young's modulus, tensile strength and fracture strain of C-S-H gel to 22.27%, 19.2% and 66.7%, respectively. The toughening mechanism in this organic/inorganic system can provide useful guidelines for polymer selection, design, and fabrication of C-S-H/polymer nanocomposites, and help eliminate the brittleness of cement-based materials from the genetic level.

First-principles Analysis of SiC/Al Composites Interface

The interface of SiCp/Al composites is an important factor affecting the properties of materials, Different interface layers have different interface bonding strengths, which have different effects on the properties of SiCp/Al composites. In this paper, the possible binding energy of interface in SiCp/Al composites is studied, then the influence of the interfacial binding energy on the SiCp/Al composites is analyzed, and the method of controlling the interface of SiCp/Al composites is proposed. Firstly, three interface models that may exist in SiCp/Al composites were constructed in Material Studio software, and the model structure was optimized, then the first-principles simulation of the optimized interfaces model of SiCp/Al composites was carried out, and the interfacial bonding energy of SiC-Al, SiC-SiO2-Al and SiC-Al2O3-Al was calculated respectively. The order of the interfacial binding energy was: SiC(100)-Al(100) < SiC(100)-SiO2 (100)-Al(100) < SiC(100)-Al2O3 (100)-Al(100). It can be known from the simulation results that the interfacial bonding energy of the interface layer containing the oxide is large, since the oxide can improve the wettability between the matrix and the reinforcement. Therefore, in order to obtain a well-bonded SiCp/Al composite, the SiC particles are usually surface-modified to regulate the interface of the SiCp/Al composite. Thereby, the SiCp/Al composite material with high interface bonding strength and excellent performance is obtained.

Factors influencing thermal transport across graphene/metal interfaces with van der Waals interactions.

We implement non-equilibrium Green's function (NEGF) calculations to investigate thermal transport across graphene/metal interfaces with interlayer van der Waals interactions to understand the factors influencing thermal conductance across the interface. It is found that interfaces with a smaller interfacial lattice mismatch, lighter metal substrate and stronger interfacial bonding strength will show better interfacial thermal transport abilities. Strain induced by the interfacial lattice mismatch in graphene is the key factor for the decrease of interfacial phonon transmission in the main frequency range of metals, which finally results in a decrease of interfacial thermal conductance. A comprehensive interfacial influencing factor is proposed combining the factors of graphene density, metal density and interfacial binding energy to realize the prediction of interfacial thermal conductance across the graphene/metal interface. The results are hoped to promote the understanding of the thermal transport mechanism and design of graphene based 2D/3D materials interfaces.